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Submission #625515

# Submission time Handle Problem Language Result Execution time Memory
625515 2022-08-10T14:14:52 Z timmyfeng Radio Towers (IOI22_towers) C++17
4 / 100
 1175 ms 67344 KB 
#include "towers.h"

#include <bits/stdc++.h>
using namespace std;

#include <bits/extc++.h>
using namespace __gnu_pbds;

template <class T>
using ordered_set = tree<T, null_type, less_equal<T>, rb_tree_tag, tree_order_statistics_node_update>;

vector<int> min_h, max_h, up, down, h;
vector<ordered_set<int>> settree;
int n;

void build(int u, int l, int r) {
	if (l + 1 == r) {
		min_h[u] = max_h[u] = h[l];
	} else {
		int m = (l + r) / 2;

		build(2 * u, l, m);
		build(2 * u + 1, m, r);

		min_h[u] = min(min_h[2 * u], min_h[2 * u + 1]);
		max_h[u] = max(max_h[2 * u], max_h[2 * u + 1]);
		up[u] = max({up[2 * u], up[2 * u + 1], max_h[2 * u + 1] - min_h[2 * u]});
		down[u] = max({down[2 * u], down[2 * u + 1], max_h[2 * u] - min_h[2 * u + 1]});
	}
}

void update(int a, int x, int u = 1, int l = 0, int r = n) {
	if (l + 1 < r) {
		int m = (l + r) / 2;
		if (a < m) update(a, x, 2 * u, l, m);
		else update(a, x, 2 * u + 1, m, r);
	}
	settree[u].insert(x);
}

void init(int n, vector<int> h) {
	::h = h, ::n = n;

	vector<pair<int, int>> points;
	for (int i = 0; i < n; ++i) {
		points.push_back({h[i], i});
	}

	sort(points.begin(), points.end());

	settree.resize(4 * n);

	set<array<int, 3>> ranges = {{INT_MIN, INT_MIN, -1}, {INT_MAX, INT_MAX, -1}};
	for (auto [hi, i] : points) {
		auto nxt = ranges.upper_bound({i, i, hi});
		auto prv = nxt; --prv;

		if (nxt->at(0) == i + 1 && prv->at(1) == i - 1) {
			update(i, hi - max(nxt->at(2), prv->at(2)));
		}

		int l = i, r = i, x = hi;
		if (nxt->at(0) == i + 1) {
			r = nxt->at(1);
			x = min(x, nxt->at(2));
			ranges.erase(nxt);
		}
		if (prv->at(1) == i - 1) {
			l = prv->at(0);
			x = min(x, nxt->at(2));
			ranges.erase(prv);
		}
		
		ranges.insert({l, r, x});
	}

	max_h.resize(4 * n);
	min_h.resize(4 * n);
	up.resize(4 * n);
	down.resize(4 * n);

	build(1, 0, n);
}

int find_first(int a, int d, int &prefix, int u = 1, int l = 0, int r = n) {
	if (r <= a) return n;
	if (l + 1 == r) {
		return max_h[u] - prefix >= d ? l : n;
	}

	if (l >= a && up[u] < d && max_h[u] - prefix < d) {
		prefix = min(prefix, min_h[u]);
		return n;
	}

	int m = (l + r) / 2;
	int b = find_first(a, d, prefix, 2 * u, l, m);
	return b == n ? find_first(a, d, prefix, 2 * u + 1, m, r) : b;
}

int find_last(int b, int d, int &suffix, int u = 1, int l = 0, int r = n) {
	if (l > b) return -1;
	if (l + 1 == r) {
		return max_h[u] - suffix >= d ? l : -1;
	}

	if (r <= b + 1 && down[u] < d && max_h[u] - suffix < d) {
		suffix = min(suffix, min_h[u]);
		return -1;
	}

	int m = (l + r) / 2;
	int a = find_last(b, d, suffix, 2 * u + 1, m, r);
	return a == -1 ? find_last(b, d, suffix, 2 * u, l, m) : a;
}

int query(int a, int b, int d, int u = 1, int l = 0, int r = n) {
	if (a >= b || b <= l || r <= a) return 0;
	if (a <= l && r <= b) return settree[u].size() - settree[u].order_of_key(d);
	int m = (l + r) / 2;
	return query(a, b, d, 2 * u, l, m) + query(a, b, d, 2 * u + 1, m, r);
}

int max_towers(int l, int r, int d) {
	int temp = h[l];
	l = find_first(l, d, temp);
	temp = h[r];
	r = find_last(r, d, temp);

	return 1 + query(l, r + 1, d);
}

Subtask #1
4.0 / 4.0

# Verdict Execution time Memory Grader output
1 Correct 470 ms 23884 KB Output is correct
2 Correct 773 ms 39820 KB Output is correct
3 Correct 1016 ms 39752 KB Output is correct
4 Correct 1025 ms 39872 KB Output is correct
5 Correct 1012 ms 39736 KB Output is correct
6 Correct 988 ms 39836 KB Output is correct
7 Correct 720 ms 39740 KB Output is correct
8 Correct 0 ms 208 KB Output is correct
9 Correct 2 ms 1104 KB Output is correct
10 Correct 1 ms 976 KB Output is correct

Subtask #2
0 / 11.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 464 KB Output is correct
2 Incorrect 4 ms 1488 KB 1st lines differ - on the 1st token, expected: '292', found: '285'
3 Halted 0 ms 0 KB -

Subtask #3
0 / 12.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 464 KB Output is correct
2 Incorrect 4 ms 1488 KB 1st lines differ - on the 1st token, expected: '292', found: '285'
3 Halted 0 ms 0 KB -

Subtask #4
0 / 14.0

# Verdict Execution time Memory Grader output
1 Incorrect 1175 ms 67344 KB 4th lines differ - on the 1st token, expected: '13956', found: '13955'
2 Halted 0 ms 0 KB -

Subtask #5
0 / 17.0

# Verdict Execution time Memory Grader output
1 Incorrect 433 ms 15624 KB 1st lines differ - on the 1st token, expected: '7197', found: '7126'
2 Halted 0 ms 0 KB -

Subtask #6
0 / 19.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 464 KB Output is correct
2 Incorrect 4 ms 1488 KB 1st lines differ - on the 1st token, expected: '292', found: '285'
3 Halted 0 ms 0 KB -

Subtask #7
0 / 23.0

# Verdict Execution time Memory Grader output
1 Correct 470 ms 23884 KB Output is correct
2 Correct 773 ms 39820 KB Output is correct
3 Correct 1016 ms 39752 KB Output is correct
4 Correct 1025 ms 39872 KB Output is correct
5 Correct 1012 ms 39736 KB Output is correct
6 Correct 988 ms 39836 KB Output is correct
7 Correct 720 ms 39740 KB Output is correct
8 Correct 0 ms 208 KB Output is correct
9 Correct 2 ms 1104 KB Output is correct
10 Correct 1 ms 976 KB Output is correct
11 Correct 1 ms 464 KB Output is correct
12 Incorrect 4 ms 1488 KB 1st lines differ - on the 1st token, expected: '292', found: '285'
13 Halted 0 ms 0 KB -